1. Field of the Invention
The present invention relates to a technique for reducing the power consumption of a control apparatus for a vehicle that outputs drive signals to an electric component installed in the vehicle.
2. Description of the Related Art
Japanese Unexamined Patent Publication No. 11-263179 discloses a vehicle control apparatus that is configured to be switched to a power saving mode in either a state where an ignition switch is off or a state where the vehicle is stopped, and is configured to return to a normal mode in a state where the ignition switch is on or the brake is operated.
The above-described conventional vehicle control apparatus is, however, switched to the power saving mode in a state where the vehicle is stopped and therefore, various kinds of electric components installed in the vehicle cannot be controlled anymore.
For example, in a case where a normally-closed type solenoid valve is provided in a fresh air induction port of a canister that collects fuel vapour generated in a fuel tank, it is necessary to open the solenoid valve upon refuelling, in order to allow the fuel tank to be opened toward the atmosphere via the canister.
However, if the control apparatus is in power saving mode, a supply of current cannot be sufficient for activating the solenoid valve. Therefore, it is necessary to hold the control apparatus in normal mode in order to enable refueling.
However, if the control apparatus is operated in normal mode while the engine is stopped, the power consumption of the control apparatus increases, and hence there is a problem such that the battery will be depleted.